The present invention relates generally to unloading systems, and more particularly, to container unloading systems that selectively and automatically cycle carts carrying unit loads, such as containers or parts bins, to the front of the system where the load is held at an angle for unloading and then cycles the carts and unloaded unit containers to the rear of the system for loading. Holding the container and load at an angle increases the ease in which objects can be removed from the container which can lead to increases in productivity.
While this invention has applications in a wide range of industries, it is particularly useful to assembly line manufacturing. In this type of operation, an important consideration is supplying the line worker with a constant stream of parts. Another important consideration is ease of access to the parts. Any delay in the parts stream or difficulties in obtaining parts can lead to inefficiencies of the entire assembly line.
While return systems, such as described in U.S. Pat. No. 5,170,896 entitled "Pallet Return Pallet Rack System," can cycle carts carrying unit loads, these systems would not make suitable container unloading systems. First, these return systems do not increase access to the container since they use gradually inclined rails and do not include sections of increased angularity. Second, without sections of increased angularity, the height of the container and cart used is limited by the vertical distance between the systems' upper and lower rails. Since this vertical distance is typically less than the height of a suitable parts bin or container, return systems, again, would not be practical as container unloading devices.
Consequently, one of the advantages of a pallet return system is that it can supply a steady stream of parts to the front of the system for use by the worker. However, in some applications, it may be necessary to provide a way to improve the access to the parts by the worker and to provide a system that could be used with suitable parts bins or containers.